The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
It is known to provide heating, ventilation, and air conditioning (HVAC) systems in vehicles. These systems heat and cool the air within the passenger compartment for the comfort of the vehicle passengers. Some vehicle HVAC systems can be selectively configured to change the source of air. In one configuration, the HVAC system draws in air from outside the vehicle, conditions the air, and then pumps the conditioned air into the passenger compartment. In another configuration, the HVAC system draws in air from inside the passenger compartment, conditions the air, and then recirculates the air into the passenger compartment. In still another configuration, the HVAC system draws in a mixture of exterior air and interior air, conditions the mixed air, and then pumps the conditioned air into the passenger compartment. In the “mixture” configuration, the passengers receive a portion of fresh air, which can reduce window fogging and also make riding in the vehicle more pleasant. In the mixture configuration, the passengers receive a portion of recirculated air while fuel economy is increased.
Although these vehicle HVAC systems have worked for their intended purposes, some disadvantages remain. For instance, these HVAC systems typically include an exterior air intake vent through which exterior air enters the system, and these HVAC systems typically include a separate interior air intake vent through which the interior air enters the system. In the “mixture” configuration described above, both the exterior and interior air intake vents are open. As such, it is possible for exterior air to enter through the exterior air intake vent and leak into the passenger compartment through the interior air intake vent. As such, the leaked exterior air enters the passenger compartment before being heated or cooled. This problem is especially likely to occur when the vehicle is traveling at higher rates of speed because the pressure of the exterior air entering the HVAC system (i.e., the “RAM air”) is relatively high.
As an example, on a warm day, warm exterior air can enter the HVAC system through the exterior air intake vent and leak into the passenger compartment through the interior air intake vent without being cooled. The warm air thus raises the temperature inside the passenger compartment, making the HVAC system expend more energy to cool the passenger compartment. As a result, fuel economy of the vehicle decreases. Accordingly, there remains a need for an improved HVAC system that draws in a mixture of exterior air and interior air for conditioning and that eliminates the amount of exterior air that leaks into the passenger compartment via the interior air intake vent.